Absolute reference aerosol sampler
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsRobert W. Doherty, Paul J. DeLuca
Life of this patent
Estimating the term…
Abstract
An absolute reference aerosol sampler system and method based on isokinetic and isoaxial sampling principles wherein the position of a collection inlet for an aerosol sampling head is adjusted relative to the actual wind direction in real time. In addition, flow rate of the air at a collection inlet within the absolute-reference sampler is matched to the real time actual wind speed. These adjustments and controls enable the absolute reference sampler system to obtain particulate samples from the immediate environment without biasing the size distribution in any manner, resulting in a fully unbiased, representative sample.
Claims19
An absolute reference aerosol sampler system, comprising:
- (a) a positioning component, comprising:
- a sampling head having a collection inlet;
- means for determining wind direction, wherein said wind direction is determined in real time,
- means for comparing the position of said collection inlet and said determined wind direction, wherein a differential value is created;
- and,
- means for positioning said sampling head reactive to said differential value and operably connected to said sampling head, wherein said means for positioning said sampling head rotates said sampling head for isoaxial alignment with said determined wind direction;
- and,
- (b) an air intake component, comprising:
- a mass flow controller;
- means for determining wind speed, wherein said wind speed is determined in real time;
- and,
- means for drawing an effective amount of ambient air into said collection inlet, wherein said mass flow controller receives an input for said determined wind speed causing said mass flow controller to regulate ambient air flow into said collection inlet to a speed substantially equivalent to said determined wind speed;
- and
- wherein said absolute reference sampler system further comprises a sealed bearing system, wherein the air flow from said sampling head remains sealed to said means for drawing ambient air into said collection inlet.
A method for ambient aerosol sampling, comprising the steps of:
- (a) providing an absolute reference sampler system, comprising:
- a positioning component, comprising:
- a sampling head having a collection inlet and a filter element;
- means for determining wind direction, wherein said wind direction is determined in real time;
- means for comparing the position of said collection inlet and said determined wind direction, wherein a differential value is created;
- and,
- means for positioning said sampling head reactive to said differential value and operably connected to said sampling head, wherein said means for positioning said sampling head rotates said sampling head for isoaxial alignment with said determined wind direction, and,
- an air intake component, comprising:
- a mass flow controller;
- means for determining wind speed, wherein said wind speed is determined in real time;
- and,
- means for drawing an effective amount of ambient air into said collection inlet, wherein said mass flow controller receives an input for said determined wind speed causing said mass flow controller to regulate ambient air flow into said collection inlet to a speed substantially equivalent to said determined wind speed;
- and,
- wherein said absolute reference sampler system further comprises a sealed hearing system, wherein the air flow from said sampling head remains sealed to said means for drawing ambient air into said collection inlet;
- and
- (b) drawing an effective amount of said ambient air into said collection inlet,
- wherein said differential value relative to said wind direction and sampling head position is calculated causing said means for positioning said sampling head to rotate said sampling head proportionally to said differential value to a calculated position;
- and,
- wherein said mass flow controller regulates the ambient air flow into said collection inlet to a speed substantially equivalent to said determined wind speed.
Dependencies are inferred from the claim text.